In a mail server, because performance worsens when processing a large volume of electronic mail, often the mail server is set so as to restrict the data amount of electronic mail, and to not send more than a predetermined data amount of electronic mail. Therefore, when transmitting a large volume of electronic mail, data of that electronic mail is divided using a message/partial format MIME (Multipurpose Internet Mail Extensions) identifier prescribed in RFC 2046. Thus, the electronic mail is transmitted such that the data amount of the electronic mail does not exceed a data amount that has been set in advance.
Also, in an image communication apparatus that reads and transmits an original, it is difficult to predict how much data will be transmitted prior to reading the original with a scanner. Therefore, there are instances in which, when attempting to transmit image data of an original that was read, the data amount is a prescribed amount or greater and so a transmission error occurs. In order to address such problems, for example in Patent Literature 1 (PTL 1), a technique is described in which image data that was obtained by reading with a scanner is divided into page units, and is transmitted such that the transmitted data amount does not exceed a prescribed value.
Also, in Patent Literature 2 (PTL 2), a technique is described in which, in a case where the data amount of electronic mail received by a mail server exceeds a restriction value, that electronic mail is transmitted after being divided.